The present invention relates to operation of remote electrical appliances wherein finding of buried power lines for an insertion of a switch is avoided by use of an energy transmitter whose location is flexible and receiver connected in the power line, usually adjacent the appliance, to perform these switching functions. The present invention is particularly characterized in affording low-cost, reliable operation, consistent with accommodating the variety of human response factors which may be involved in using such switching equipment.
It is known in the prior art to use light or sound transmitters and receivers to provide remote switching. An example of a prior art device or remote light switching is given in U.S. Pat. No. 3,584,222, granted June 8, 1971 to Nesbitt. In that device, a photoelectric transducer provides triggering current for maintaining a triac conductive to provide power to a remote appliance. At the same time a timing motor is operated to break the power line circuit after a limited time to turn off the appliance. The activating light beam can be passed through window glass thereby providing an additional worth while capability supplementing the freedom from limited location of switch and further freedom from need to seek out power lines which are buried in walls to locate a mechanical switch. It is also known to use optical switching for A.C. appliances wherein activating light beams provide both turn-on and turn-off signals to separate photoelectric transducers, as indicated for instance in U.S. Pat. Nos. 3,767,924 and 3,829,683. In the former a pair of photoelectric transducers when light activated can provide switching on and off triggering signals to a triac via a bi-stable flip-flop electronic circuit and in the latter, a pair of SCR's control operation of oppositely poled relay coils for alternatively operating a mechanical switch on and off.
It is an important object of this invention to provide a light activated semiconductive switching in response to light incident upon a single photoelectric transducer which can accommodate human handling of the light source, as opposed to fixed computer controls of activating light.
It is a further object of the invention to provide reliable, repeatable cycling in such apparatus consistent with the preceding object.
It is a further object of the invention to economically achieve one or more of the foregoing objects.
It is a further object of the invention to provide adjustability of the apparatus of the class described for utilization in different switching situations, consistent with one or more of the preceding objects.